Kairos Three Way Speakers

Above: The Satori MW16P mid-woofer. Neodymium magnet, papyrus based cone material, vented pole, copper sleeve on pole. Also with integrated gasket.

Above: I made a couple jigs from scrap wood (one shown on the right here) to route the cutouts in the baltic birch internal braces (on the left).

Above: Test fitting the drivers to the front panel, including checking the 45 degree chamfered recess in the back to allow unrestricted airflow - mandatory with extra thick baffles.

Above: The rear woofer panels. You can see the lamination of the mdf and baltic birch. Also shown is the channel I cut to route the cable from the input at the base of the woofer to the rear of the Kairos.

Above: Once the woofer cabinet was assembled and the baltic birch braces added, I applied the side damping material. For the woofers, I used the North Creek "glop" (the white stuff above), consisting of Aleenes's Tacky Glue mixed with drywall compound in a 2:1 ratio. It is applied to one side, then has to dry for a day before rotating the cabinet for the other side.

I decided to build the woofers as sealed boxes instead of vented, as I planned to use them mostly with subs, and in general like the sound of sealed systems. I'm hoping that combined with room gain, these will play low enough that I'll be happy. However, I spaced the braces to allow me to add the 3" vent per Jeff's vented design if I later decide otherwise.

Above: Woofer cabinets stained and finished. Next up: building a base...

Above: Solid 3/4" oak used for the base, during assembly. The base has 3 purposes: to raise the speakers to the correct height, add some protection for the cherry veneered cabinets from vacuum cleaners, etc, and as a location to house the woofer crossover.

Above: To mount the spiked feet, I countersunk 1/4" heavy duty T-nuts into a piece of baltic birch (shown upside down above), then glued it to the base. In this configuration, the T-nut is captive and cannot come loose.

Above: The bases are designed to be about 1/2" wider than the woofer cabinets all around, and are beveled at a 10 degree slant to mate with the woofer cabinet. Here I'm test fitting the binding posts.

Above: Bases were completed with a coat of satin black. They are mounted to the bottom of the woofers with 6 screws each, so if they get scuffed or damaged, they can be removed and repaired and/or repainted.

Above: Woofer mounted to the base. Also attached are the Soundcare Superspike feet, which have an integral base for the spike (to protect wooden floors). I've also attached the female grille mounts.

Above: The cabinets are shown here completed, and are ready for crossover assembly.

5. The Crossovers

Note: The crossover for the woofer section (both high and low pass) has graciously been made available by Jeff Bagby (see link at top of this page), so those component values are visible and/or listed in my description. The Kairos crossover is, however, proprietary, so I've obscured the values of the components. As mentioned above, the Kairos kit (and the woofer kit as well) are available from Meniscus Audio (who are very helpful and highly recommended).

Above: The woofer crossover. For the 3 ohm resistor, I used a 1% 50 watt non-inductive Dale resistor, mounted on an aluminum plate for some heatsinking. The 200uf cap is a Solen polypropylene. The cable to the right goes into the cabinet and to the woofer. All wiring for the system is AudioQuest Type 4, and I used about 16' total for both the Kairos and woofer sections. The twisted pairs of red and black cables attached to the binding posts on the left are simply jumpers going up the channel in the rear panel to connect to the Kairos.

Above: The Kairos crossovers, mounted in the base of the cabinet, binding posts are on the right side but hidden from view. I upgraded the tweeter cap to an M-Cap Supreme, and the resistors to Mills 1% 12 watt units. The 150uf cap (for the high pass section of the woofer crossover) is composed of three 50uf polypropylene caps bypassed with a 0.47uf Sonicap. The 10 Ohm resistor in the woofer crossover is upgraded, like in the low pass section, to a Dale 50 watt 1% non-inductive resistor mounted on a heatsink. Again, the values of the Kairos crossover have been obscured here as they are proprietary.

I did make one slight change from the stock Bagby crossover design. The default design calls for the 150uf high pass caps to the Kairos to be in series with the entire Kairos crossover, including the tweeter circuit. I simply bypassed the 150uf caps for the tweeter circuit, connecting that circuit directly to the inputs and eliminating the large cap from the tweeter circuit (which has its own high pass components, obviously).

6. Grilles

Although it is trendy to have speakers with no grilles, we have children and housecleaners around occasionally, so they are mandatory in my case.

Above: Fitting the grilles to the Kairos cabinets. These grilles are made of 3/8" baltic birch, and the woofer grills were made 5/8" thick to accommodate the longer excursion of the woofers.

Above: I added 1/4" thick felt around the inside of the grill near the tweeter to help control diffraction, in a similar fashion to the felt around the tweeter in the LS3/5a speakers (this felt in fact was left over from an LS3/5a repair). With this felt in place, my OmniMic measurements indicated virtually no changes in frequency response with and without the grills.

Above: A Kairos grill being assembled. For grill material, I like to use material that Magnapan uses on their speakers. It is significantly lighter and more transparent than most other grille cloth I've seen.

7. Final Assembly

Above: Cabinets with acoustic stuffing. The woofer cabinets used polyester fiberfill, and the Kairos speakers use dacron batting, per the original Bagby design. You can see the Audioquest Type 4 cable used for the entire system here, ready for driver connections.